If I tell you what I have......

[Kaptain Klevtsov]

Cool down time. Carbon fibre is sooo cool to start with.

Seriously, the carbon tube is suposed to stay the same length better as it cools during the night. If the 'scope gets shorter by enough, the focus goes off. This is bad for imaging. Coefficient of thermal expansion and all that.

Kaptain Klevtsov

[saturn5]

Is that the E(expansion)= L(lenght)alpha(coefficient of expansion of said material)delta t(temperature change of said material) type of expansion you mean? :laughing2: only formula i ever remembered from school(30 odd years ago.

[Kaptain Klevtsov]

Thats the one.

Kaptain Klevtsov